Pruning scissors

ABSTRACT

Pruning of scissors comprise a blade ( 1 ) and a counter-blade ( 2 ) each integral with a grip and mounted so as to be pivoted around a threaded swivel pin ( 10 ) cooperating with an adjusting nut ( 3 ) of the blade ( 1 ) and counter-blade ( 2 ), wherein the nut ( 3 ) is rotationally integral with a toothed wheel ( 4 ) meshed with a retainer toothed member attached to the pruning scissors counter-blade ( 2 ) through a blocking screw ( 6 ).  
     The toothed wheel ( 4 ) has an axial opening ( 11 ) whose outline ( 12 ) corresponds to the external outline ( 13 ) of the adjusting nut ( 3 ) and is adapted to be inserted around the nut ( 3 ).  
     The retainer toothed member is a toothed gear ( 5 ) and the toothed wheel ( 4 ) and the toothed gear ( 5 ) comprise respective complementary means adapted to retain the toothed wheel ( 4 ) around the nut ( 3 ) against any axial movement when the gear ( 5 ) is meshed with the toothed wheel ( 4 ).

[0001] The present invention relates to pruning scissors having a nut retainer device. This system allows to easily set the friction force of the blade and counter-blade while preventing the nut from getting loose.

[0002] Pruning scissors are known from FP-B-0 704 150, which comprise a blade and a counter-blade which are each integral with a grip and mounted so as to be pivoted around a threaded swivel pin cooperating with an adjusting nut for tightening the blade and counter-blade, wherein the nut is rotationally integral with a toothed wheel coaxial with the nut and meshed with a retainer toothed member attached to the counter-blade through a blocking screw.

[0003] Such scissors have the drawback of including an adjusting nut of complex shape and therefore high cost. Specifically, such a nut will have an internal thread for screwing the same onto the blade and counter-blade swivel pin and an external profile allowing it, on the one hand, to be handled by means of a tool such as a wrench or pliers and, on the other hands to be meshed with the nut retainer.

[0004] Another drawback of such pruning scissors is that the retainer member has a circular sector shape with a small center angle such that, when adjusting the blade and counter-blade friction force (unblocking the retainer, adjusting the nut and blocking the retainer), it readily becomes loose from the nut. Then, the user has to disassemble the retainer member in order to re-mesh the retainer member with the nut. This is also the case when partially or entirely disassembling the pruning scissors.

[0005] The present invention aims at providing pruning scissors of the above mentioned type which have a nut retainer system preventing any angular or axial movement of the nut and whose manufacturing cost is reduced. Another object of the present invention is to provide a retainer member which remains meshed with the adjusting nut during friction adjustment operations of the blade and counter-blade, whether such adjustment is critical or not.

[0006] According to the present invention, the above mentioned pruning scissors are characterized in that the toothed wheel is separate from the nut, has an axial opening whose outline corresponds to the external outline of the adjusting nut and is adapted to be inserted around the nut, in that the retainer toothed member is a toothed gear and in that the toothed wheel and toothed gear comprise respective complementary means adapted to retain the toothed wheel around the nut against any axial displacement when the gear is meshed with the toothed wheel.

[0007] Thus, it is possible to use a conventional nut as the adjusting nut. The toothed wheel has a simple profile and, most important, can be made of a material of lower strength than that of the nut, since the mechanical stress it undergoes is much smaller. Great savings can thus be made by use of the present invention. Moreover, because the retainer toothed member is a gear, it can remain permanently in contact with the toothed wheel during friction adjustment operations of the blade and counter-blade. Finally, the respective complementary means of the gear and toothed wheel prevent any axial movement of the toothed wheel, and the gear system stops all angular movements. Thus, pruning scissors are obtained, which comprise a very simple and reliable system for adjusting the blade and counter-blade tightening.

[0008] According to a first embodiment of the present invention, the toothed wheel is integral with a washer interposed between the toothed wheel and the counter-blade of the pruning scissors. The diameter of this washer is greater than the outer diameter of the wheel teeth. The gear is at the same level as the toothed wheel, for instance, by means of a second washer interposed between the scissors counter-blade and the gear.

[0009] Thus, the gear teeth cover the peripheral edge of the washer, thereby preventing any axial displacement of the toothed wheel.

[0010] According to a second embodiment of the invention, a ring, which is coaxial with the gear, is placed in such a position that the gear is positioned between the scissors counter-blade and the ring. This ring has a greater diameter than the outer diameter of the gear teeth.

[0011] Thus, the peripheral edge of the ring covers the wheel teeth and prevents any axial displacement of said toothed wheel.

[0012] In the appended drawings, given by way of non limiting example:

[0013]FIG. 1 is a substantially front, perspective view of pruning scissors according to one embodiment of the invention;

[0014]FIG. 2 is an enlarged perspective, substantially lateral view of a feature of the pruning scissors of FIG. 1;

[0015]FIG. 3 is a perspective substantially three-quarter view of the feature shown in FIG. 2;

[0016]FIG. 4 shows a first embodiment according to the present invention; and

[0017]FIG. 5 shows a second embodiment according to the present invention.

[0018] FIGS. 1 to 3 show pruning scissors having a blade 1 and a counter-blade 2. An adjusting nut 3 for fastening blade 1 and counter-blade 2 is screwed to an end of a threaded swivel pin 10 for blade 1 and counter-blade 2. A toothed wheel 4 having an axial opening 11 whose outline 12 corresponds to the external outline 13 of adjusting nut 3 is inserted around nut 3 and therefore made integral with angular movements of adjusting nut 3.

[0019] A nut retainer system consisting of a gear 5 is attached to the scissors counter-blade 2 by means of a blocking screw 6. As the gear 5 is toothed along its circumference, it remains meshed within toothed wheel 4 whatever the amplitude of the angular movement for tightening or loosening the nut 3.

[0020] In this way, tightening gear 5 by means of blocking screw 6 onto counter-blade 2 of the pruning scissors blocks toothed wheel 4 through a meshing action. Due to the profile of axial opening 11 in toothed wheel 4, adjusting nut 3 is itself stationary, whatever the number of cuts performed by the user of the pruning scissors and the tightening strength of blade 1 and counter-blade 2.

[0021] Toothed wheel 4 is axially blocked by complementary respective means provided in toothed wheel 4 and gear 5 more specifically shown in FIGS. 2 to 5.

[0022] According to a first embodiment of the present invention, as shown in FIGS. 2 to 4, a washer 14 integral with toothed wheel 4 is axially interposed between toothed wheel 4 and counter-blade 2 of the pruning scissors. The diameter of this washer 14 is greater than the outer diameter of the teeth of toothed wheel 4. Gear 5 is raised to the height of toothed wheel 4 by means of a second washer 7. Thus, washer 14 is kept between scissors counter-blade 2 and gear 5. Toothed wheel 4, since it is integral with washer 14, cannot move axially.

[0023] Washer 14 can thus be made integral with toothed wheel 4. Alternatively, washer 14 can be separate from toothed wheel 4 but can be made integral therewith, for example, by gluing.

[0024] According to a second embodiment of the present invention, as shown in FIG. 5, it is possible to use, as means for preventing axial movement of toothed wheel 4, a ring 15, coaxial with gear 5, with a diameter greater than the outer diameter of the teeth of gear 5. This ring 15 is placed in such a way that gear 5 is located between the pruning scissors counter-blade 2 and said ring 15. Thus, toothed wheel 4 is retained between the pruning scissors counter-blade 2 and ring 15.

[0025] Of course, the present invention is not restricted to the above described embodiments.

[0026] Gear 5, toothed wheel 4, washer 14, washer 7 and ring 15 can for example be made of a fiber-impregnated plastic material.

[0027] The second washer 7 can be made integral with gear 5 or separate from said gear. It can be replaced by a corresponding boss formed on the surface of counter-blade 2.

[0028] The pruning scissors, through a simple structure (a conventional nut used as the adjusting nut) which is reliable and cost-effective (and a toothed wheel independent of the nut, which can be made of a weaker material than that of the nut), allow the nut to be rotated by a whole revolution or more thereby enabling faster and better cleaning of the pruning scissors and an easy adjustment thereof by maintaining the gear and toothed wheel permanently meshed together, that is without having to disassemble the components. 

1. Pruning scissors comprising a blade (1) and a counter-blade (2) each integral with a grip and mounted so as to be pivoted around a threaded swivel pin (10) cooperating with an adjusting nut (3) of the blade (1) and counter-blade (2), wherein the nut (3) is rotationally integral with a toothed wheel (4) meshed with a retainer toothed member attached to the scissors counter-blade (2) through a blocking screw (6), characterized in that the toothed wheel (4) is separate from nut (3) and has an axial opening (11) whose outline (12) corresponds to the external outline (13) of the adjusting nut (3) and is adapted to be inserted around the nut (3), in that the retainer toothed member is a toothed gear (5), and in that the toothed wheel (4) and toothed gear (5) comprise respective complementary means adapted to retain the toothed wheel (4) around the nut (3) against any axial displacement when the gear (5) is meshed with the toothed wheel (4).
 2. Pruning scissors according to claim 1, characterized in that the toothed wheel (4) is interdependent with a washer (14) interposed between the counter-blade (2) and the toothed wheel (4), whose diameter is greater than the outer diameter of the teeth of said wheel (4) and in that the gear (5) is positioned at the same level as the toothed wheel (4), for example by means of a second washer (7) interposed between the counter-blade (2) and the gear (5).
 3. Pruning scissors according to claim 2, characterized in that washer (14) is integral with the toothed wheel (4).
 4. Pruning scissors according to claim 2, characterized in that the washer (14) is separate from the toothed wheel (4) and is made integral therewith, for example by gluing.
 5. Pruning scissors according to claim 1, characterized in that it comprises a ring (15), co-axial with the gear (5), which is positioned so that the gear (5) is located between the counter-blade (2) and the ring (15), and has a greater diameter than the outer diameter of the teeth of the gear (5).
 6. Pruning scissors according to any of the preceding claims, characterized in that the toothed wheel (4) and gear (5) and, when applicable, washers (14, 7) or ring (15) are made of a fiber-impregnated plastic material. 